There are various applications which require the use of such a conveyor or chain, such as, for instance, continuous transport mechanisms wherein an endless chain is used, the variable length links of which allow accelerating the transport speed in some zones, while reducing said speed in other zones.
This principle is used, in particular, in speeding up systems for pedestrian movement, or escalators, which are continuous conveyors upon which pedestrians step. If the endless chain of the conveyor includes variable length links, it will be possible to accelerate the rate of motion of the pedestrians in the zones where a suitable arrangement increases the length of the links. In this case, certain elements of the chain are periodically made integral with a carriage, the latter generally carrying combs.
Most of the known systems for obtaining accelerating or decelerating arrangements are heavy, complicated, and cumbersome. Moreover, said systems cannot be wound, that is, the plane defined by the transport surface of the links is necessarily perpendicular to the return axes located at both ends of the system. This prevents obtaining systems which take up little space with a view to provide, for instance, a handrail intended to accompany an escalator, which handrail should wind about end return axes perpendicular to the plane of transport, so that the return zone could be accommodated under the upgoing zone.
An object of the present invention is to obviate said drawbacks by providing a chain with links of variable length, the original design of which allows constructing it simply and with any dimensions whatever. In addition, the chain according to the invention and the control system therefor are able to wind about two end pulleys to form an endless circuit, the carrying surface of which is parallel to the axes of said pulleys. It can also be adapted to an arrangement of the "roundabout" type, wherein the endless carrying surface is perpendicular to the axes of the pulleys.